Eyes should be crocheted with thread which is 4 times thinner than the thread used for the body. I use YarnArt Jeans for the body and it is a yarn that can be untwisted into four thinner threads so I just untwist it and use a single thread.

This is how I make both eyes:

Start with a magic ring and make the first row in black, the second and third in purple, and the fourth in white. Leave long thread ends (you will need them to sew eyes to the head).

After you finish both eyes, use white thread end to embroider white highlights. Then sew eyes to Celestia’s head and embroider black borders and eyelashes as shown in picture below. The borders should be embroidered with a full-thick thread. Check the chart below to see where the seams should go.